Within recent years a growing series of small, single operator, rough terrain vehicles has evolved based on a combination of motorcycle and tricycle technology. These units involve the use of large, low pressure, balloon tires in a tripod pattern, with special off-road traction surfaces for transporting a single operator and some cargo through undeveloped or roadless terrain.
These machines have proven especially popular with hunters, who use them to reach backwood areas and remote rural areas. An extensive market has grown up supporting this type of activity.
Within the bayous of Southern Louisiana and similar coastal regions, a terrain condition arises which inhibits the mobility of an operator on such a device. In essence, the terrain consists of mixed land, marsh and open water area. Any significant mobility in such country requires that the three-wheeler motorcycle have the capability of traversing marsh or open-water area, both of which have insufficient mechanical support to hold the motorcycle up by displacement against the tires. The large, the low pressure balloon-tire design of a three-wheel motorcycle of common off-road design, is such that the motorcycle will operate successfully in areas of heavy mud and other soils having low load-bearing characteristics; the overall weight of the motorcycle plus operator is such that the tires provide insufficient water bouyancy to actually float the motorcycle. Further, were the tires to have sufficient flotation to displace enough water to float the entire motorcycle, the center of gravity of the motorcycle would be sufficiently far above the center of flotation so that the overall unit would be unstable and dangerous to operate.
Various forms of outriggers or pontoons have been designed for off-road vehicles, including both motorcycles and standard four-wheel vehicles. These pontoons suffer a number of disadvantages in rough terrain work.
The principal disadvantage of these prior art designs is that the majority of the prior art pontoons are fixed in position by rigid mechanical braces, being removable only by the removal of bolts, nuts and the like; they cannot be moved between positions while the vehicle is in operation. As a result, a pontoon equipped vehicle is required to have its pontoons permanently extended in a downward floatation position; this requires that the vehicle only be operated in types of terrain where there are few or no obstacles close to the ground and where there is little change in the terrain gradiant or slope. Further, since the pontoons must maintain adequate ground clearance for the vehicle to enter and exit water using traction drive by wheels, the pontoons must be fixed higher than is desirable for optimal flotation.
Thus, if a motorcycle were to have pontoons of standard design, the lower part of the motorcycle, including the operator's foot pedals, a significant portion of the gear casing, the oil pan, and related mechanisms would be permanently immersed in the water. Thus creates a high drag situation when the pontoon equipped motorcycle is actually in the water, inhibits the ability of the motorcycle to be propelled through the water, and creates a permanent discomfort for the operator.
Further, many outrigger designs, in an effort to overcome the necessity of clearing underbrush terrain clearance, do so by locating the pontoons as close as is mechanically practical to the sides of the vehicle attempting to create a narrow vehicle. Locating the pontoons this close to the vehicle creates a very unstable situation as the center of gravity can rapidly be displaced over the center of flotation of the structure as the structure lists. As is known in the art of stability in floating vehicles, this can create a catastrophic flip. Further, as in the case of all catamarand or dual flotation systems, once the unit turns over, it is unconditionally stable in the upside-down position and cannot normally be recovered from that position by the efforts of the operator.
Further, since the average motorcycle or rough terrain vehicle is a single operator device, such instability can be extremely dangerous as it is entirely conceivable that the operator will be alone when the vehicle flips. This produces a situation in which an operator can be trapped or pinned by a dangerous vehicle in a remote wild area with no hope of rescue and no availability of help.